/in/foo.cc: In function 'double eular(int)':
/in/foo.cc:9:12: warning: unused variable 'i' [-Wunused-variable]
  int ret=1,i;
            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:38:16: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'int' [-Wformat=]
  printf("%ld",n);
                ^